Adjustment Device with a Dual-Guiding Structure

ABSTRACT

An adjustment device with a dual-guiding structure has two worm wheels respectively meshed with two coaxial worm rods (the worm wheel and worm shaft structure is an application of gear and threaded rod). Two worm rods are pivotally and longitudinally fixed by a driving shaft in line. An adjacent end of each worm rod has a locking recess to receive a locking head mounted on the driving shaft. Thereby, the locking head is selectively engaged with one corresponding locking recess to drive the corresponding worm rod when the locking head on the driving shaft moves in reciprocation. Then, one worm wheel engaged with the corresponding worm rod is rotated to make the wires on the work wheel to rewind or release.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an adjustment device, and moreparticularly to an adjustment device composed of two worm rods coaxiallycombined together, two worm wheels respectively engaged with the twoworm rods, and a shaft with a locking device to selectively controlwires thereon.

2. Description of Related Art

A wire-guiding adjustment device is a structure for winding andreleasing wires to drive position variation of a relative element bycontrolling the released length of the wires. For example, once an upperend and a lower end of a resilient backrest are controlled by the wires,the resilient backrest is bent to a big curved arc when the wires arereleased shorter. On the contrary, when the wires are released longer,the resilient backrest rebounds to keep straight. Therefore, thewire-guiding adjustment device has a wide application and variousmodifications in structures.

A conventional wire-guiding adjustment device is limited in technicalaspect and generally comprises a single guiding wheel that can beselectively arranged to receive one or two counter wires tosynchronously operate the wires for changing the shape or position ofattached element such as the resilient backrest. However, controllingthe resilient backrest usually needs multiple sets of the wire-guidingadjustment devices. For example, two conventional wire-guidingadjustment devices are needed for arc control and height control of theresilient backrest in operation so that setting the resilient backrestwith the wire-guiding adjustment devices is not only cost-wasting butalso time-consuming because it is hard to find proper locations andspaces for multiple sets to keep neat in appearance and also confusingin functions to users.

SUMMARY OF THE INVENTION

A main objective of the present invention is to provide an adjustmentdevice with a dual-guiding structure that is composed of two worm rods,a shaft penetrating the two worm rods, and two worm wheels respectivelyengaged with the worm rods so that the adjustment device enables toreceive multiple wires on the at least two worm wheels formulti-functional controlling.

main objective of the present invention is to provide an adjustmentdevice with a dual-guiding structure that is convenient in assembly forworkers and in operation for users.

To achieve the foregoing objectives, the adjustment device with adual-guiding structure comprises:

two wire-guiding sets, each wire-guiding set having a worm wheel;

two worm rods coaxially combined together and respectively meshing withthe worm wheels on the two wire-guiding sets, wherein each worm rod hasan adjacent end and a locking recess defined in the adjacent end; and

a driving shaft axially penetrating the two worm rods and having alocking head mounted on the driving shaft to selectively engage with thelocking recess on the worm rod.

Thereby, the two wire-guiding sets can be selectively and convenientlycontrolled by the driving shaft to control the rewind and release of thewire.

Further benefits and advantages of the present invention will becomeapparent after a careful reading of the detailed description withappropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an adjustment device with a dual-guidingstructure in accordance with the present invention;

FIG. 2 is a perspective view of the adjustment device with adual-guiding structure that combines with multiple wires in operation;

FIG. 3 is a cross-sectional side view of the adjustment device with adual-guiding structure in FIG. 1;

FIG. 4 is an operational cross-sectional side view of the adjustmentdevice with a dual-guiding structure;

FIG. 5 is another operational cross-sectional side view of theadjustment device with a dual-guiding structure;

FIG. 6 is partially exploded perspective view of one embodiment of adriving shaft in the adjustment device; and

FIG. 7 is partially exploded perspective view of another embodiment of adriving shaft in the adjustment device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An adjustment device with a dual-guiding structure in accordance withthe present invention has two worm wheels respectively meshed with twocoaxial worm rods (the worm wheel and worm shaft structure is anapplication of gear and threaded rod). Two worm rods are pivotally andaxially fixed by a driving shaft. An adjacent end of each worm rod has alocking recess to receive a locking head mounted on the driving shaft.Thereby, the locking head is selectively engaged with one correspondinglocking recess to drive the corresponding worm rod when the locking headon the driving shaft moves in reciprocation. Then, one worm wheelengaged with the corresponding worm rod is rotated to make the wires onthe work wheel to rewind or release.

For more modification, the adjustment device selectively comprises atleast two rods and at least two worm wheels respectively engaged withthe worm rods so that the adjustment device enables to receive multiplewires on the at least two worm wheels for multi-functional controlling.

A preferred embodiment of the adjustment device with a dual-guidingstructure has two wire-guiding set 1 each with a worm wheel 11 (as shownin FIGS. 1 and 2), two worm rods 2, a driving shaft 31, and a lockinghead 3. The wire-guiding set 1 is composed of the worm wheel 11 and areel mounted over the worm wheel 11 to collect the wires 13 woundthereon. The two worm rods 2 are coaxially combined together by thedriving shaft 3 to mesh with the two worm wheels 11. The locking head 31is formed on a middle section of the driving shaft 3. Each worm rod 2has an adjacent end and a locking recess 21 defined at the adjacent endto correspondingly face another locking recess on the other worm rod 2as shown in FIG. 3 and to operationally receive the locking head 31 fordriving control. Moreover, a sleeve (301) spaces the two worm rods 2 toperform a chamber (302) between the two adjacent ends to accommodate thelocking head 31 when both worm rods 2 are set free. When the lockinghead 31 on the driving shaft 3 is engaged with one corresponding lockingrecess 21 of the relative worm rod 2, the worm rod 2 is driven to rotatethe engaged worm wheel 11 so that the wire 13 on the wire-guiding set 1is rewound or released.

According to above described structure, a wire ring 12 on thewire-guiding set 1 is for attaching the wire 13. The wire-guiding set 1enables to set one or more than two wire ring 12 to combine more wiresfor different operational purposes (because attaching one or two wireson the wire-guiding set is conventional, redundant description iseliminated). The rotation of the wire-guiding set 1 controls the rewindor the release of the wire 13. Because the worm wheel 11 on thewire-guiding set 1 meshes with the worm rod 2, the wire-guiding set 1 ispositioned by the worm rod 2 when the driving shaft does not rotate (theworm rod 2 drives the worm wheel 11 but the worm wheel 11 can not drivethe worm rod 2 in reverse). Therefore, the worm rod 2 efficientlycontrols the wire 13 on the wire-guiding set 1. When the locking head 31on the driving shaft 3 slides into one corresponding locking recess 21on the corresponding worm shaft 2 (as shown in FIGS. 4 and 5). Therotation of the driving shaft 3 drives the worm rod 2 engaged with thelocking head 31 to control the wire 13. In the same manner, another wormshaft 2 is driven when the locking head 31 slides into the lockingrecess 21 of the worm shaft 2. Therefore, the two wire-guiding sets 1can be selectively operated by the same driving shaft 3 to performdifferent functions.

To make the locking head 31 smoothly and easily to engage with thelocking recess, the locking head 31 has two distal ends and a leadingangle 311 at each distal end (as shown in FIGS. 6 and 7), i.e., eachdistal end is tapered in cross-section. Preferably, the locking head 31is polygonal and the locking recess 21 is polygonal in correspondence toprovide sufficient driving force. The shape of the locking head 31 andthe locking recess 21 can be modified and not limited in hexagonal orstar-shape as shown in FIGS. 6 and 7.

Moreover, the wire rings 12 on the two wire-guiding sets 1 are arrangedin different heights (as shown in FIG. 2) to perform a height differenceto make the wires 13 to extend outward without tangling concern.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentinvention of the preferred form has been made only by way of example andthat numerous changes in the details of construction and the combinationand arrangement of parts any be resorted to without departing from thespirit and scope of the invention.

1. An adjustment device with a dual-guiding structure comprising twowire-guiding sets, each wire-guiding set having a worm wheel; two wormrods coaxially combined together and respectively meshing with the wormwheels on the two wire-guiding sets, wherein each worm rod has anadjacent end and a locking recess defined in the adjacent end; and adriving shaft axially penetrating the two worm rods and having a lockinghead mounted on the driving shaft to selectively engage with the lockingrecess on the worm rod.
 2. The adjustment device with a dual-guidingstructure as claimed in claim 1, wherein the locking head has two distalends and two leading angle formed respectively at the two distal ends.3. The adjustment device with a dual-guiding structure as claimed inclaim 1, wherein each of the two wire-guiding set comprises a reelmounted over the worm wheel and having at least one wire ring attachedto the reel; and at least one wire respectively attached to the at leastone wire ring and wound on the reel.
 4. The adjustment device with adual-guiding structure as claimed in claim 1, wherein a sleeve spacesthe two worm rods to perform a chamber between the two adjacent ends toaccommodate the locking head.